A recovery cryostat, external to a cryogen storage tank, uses a cryocooler to condense vapor of cryogen from the storage tank and return the cryogen to the storage tank as a liquid. The process may be continuous or cyclical depending on the orientation of the recovery cryostat. If the recovery cryostat is located such that liquid can drain back to the storage tank, the process can be continuous. If the liquid cannot be drained back, a valve on the liquid return line is closed while the cryocooler condenses the vapor, a valve on the vapor supply line is then closed, the valve on the liquid return line is opened, and pressure in the recovery cryostat is increased to drive the liquid out. The storage tank is a type that can have vapor that boils off external to the tank be returned to the vapor space above the liquid in the tank.
A recovery cryostat, external to a cryogen storage tank, uses a cryocooler to condense vapor of cryogen from the storage tank and return the cryogen to the storage tank as a liquid. The process may be continuous or cyclical depending on the orientation of the recovery cryostat. If the recovery cryostat is located such that liquid can drain back to the storage tank, the process can be continuous. If the liquid cannot be drained back, a valve on the liquid return line is closed while the cryocooler condenses the vapor, a valve on the vapor supply line is then closed, the valve on the liquid return line is opened, and pressure in the recovery cryostat is increased to drive the liquid out. The storage tank is a type that can have vapor that boils off external to the tank be returned to the vapor space above the liquid in the tank.
F25J 1/02 - Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen
F17C 13/00 - Details of vessels or of the filling or discharging of vessels
3.
Thermal Insulation System for a Capacitance Diaphragm Gauge
A capacitance diaphragm gauge (CDG) assembly includes a CDG sensor positioned within a vacuum enclosure, which is maintained at a vacuum. The CDG sensor generates sensor signals responsive to a pressure of an applied gas. The vacuum enclosure provides thermal insulation around the CDG sensor. The CDG sensor is maintained at a selected operating temperature using an internal heater positioned on the CDG sensor. The internal heater is responsive to external heater control signals. The temperature of the CDG sensor is monitored using an internal temperature sensor mounted on the CDG sensor. The temperature sensor generates a temperature signal. The vacuum enclosure includes an end cap that seals the vacuum enclosure. Connectors positioned through the end cap communicate the sensor signals, the heater control signals and the temperature signals through the end cap. The connectors are hermetically sealed to the end cap to maintain the vacuum within the vacuum enclosure.
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
A capacitance diaphragm gauge (CDG) assembly includes a CDG sensor (140) positioned within a vacuum enclosure (110), which is maintained at a vacuum. The CDG sensor generates sensor signals responsive to a pressure of an applied gas. The vacuum enclosure provides thermal insulation around the CDG sensor. The CDG sensor is maintained at a selected operating temperature using an internal heater positioned on the CDG sensor. The internal heater is responsive to external heater control signals. The temperature of the CDG sensor is monitored using an internal temperature sensor mounted on the CDG sensor. The temperature sensor generates a temperature signal. The vacuum enclosure includes an end cap (180) that seals the vacuum enclosure. Connectors positioned through the end cap communicate the sensor signals, the heater control signals and the temperature signals through the end cap.
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
G01L 19/00 - Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
The object of this invention is to increase the life of the displacer and stem seals of the reciprocating displacer of a Gifford McMahon (GM) cryogenic expander. The seal comprises a ring that is relatively long and thin and uses the pressure difference across the seal, acting behind the ring, as the primary force to bring the ring into contact with the cylinder and stem walls. The pressure difference across the seal ring pushes the ring to one end of the groove, and the friction force pushes the ring in the same direction while it is moving. The sealing force is distributed over a larger area compared with a conventional backed "O" ring thus reducing the wear rate and increasing the seal life.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
The object of this invention is to increase the life of the displacer and stem seals of the reciprocating displacer of a Gifford McMahon (GM) cryogenic expander. The seal comprises a ring that is relatively long and thin and uses the pressure difference across the seal, acting behind the ring, as the primary force to bring the ring into contact with the cylinder and stem walls. The pressure difference across the seal ring pushes the ring to one end of the groove, and the friction force pushes the ring in the same direction while it is moving. The sealing force is distributed over a larger area compared with a conventional backed “O” ring thus reducing the wear rate and increasing the seal life.
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
F16J 9/26 - Piston-rings, seats thereforRing sealings of similar construction in general characterised by the use of particular materials
F16J 9/20 - Rings with special cross-sectionOil-scraping rings
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
7.
SUPERCONDUCTING MAGNET DEVICE, AND COOLING METHOD FOR SUPERCONDUCTING MAGNET DEVICE
A superconducting magnet device includes a superconducting coil; a radiation shield that thermally protects the superconducting coil; a main cold head that cools the superconducting coil; a sub-cold head that cools the radiation shield; a common compressor that supplies a refrigerant gas to the main cold head and the sub-cold head; a first temperature sensor that measures a temperature of the radiation shield; a second temperature sensor that measures a temperature of the superconducting coil; and a controller configured to activate the sub-cold head for initial cooling of the superconducting magnet device, stop the sub-cold head based on an output of the first temperature sensor or the second temperature sensor, and operate the main cold head in a state where the sub-cold head is stopped.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
H01F 6/06 - Coils, e.g. winding, insulating, terminating or casing arrangements therefor
A circulating loop for transporting refrigeration to a remote location is connected serially between a Gifford-McMahon (GM) or GM type Pulse Tube cold head and the compressor. Either high pressure gas from the compressor can flow through the remote heat station before returning to the cold head or low pressure gas can flow from the cold head to the remote heat station before returning to the compressor. A first fraction of gas, which may include all of the gas at ambient temperature, enters a counter-flow heat exchanger, is cooled by the cold head, flows to the remote load, and then returns to ambient temperature as it flows through the counter-flow heat exchanger. The high or low pressure line may have a circulation control valve that diverts a second fraction of gas to flow directly between the cold head and compressor. A controller adjusts the circulation control valve to optimize the cooling of the load.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 1/00 - Compression machines, plants or systems with non-reversible cycle
F25B 41/20 - Disposition of valves, e.g. of on-off valves or flow control valves
F25B 41/45 - Arrangements for diverging or converging flows, e.g. branch lines or junctions for flow control on the upstream side of the diverging point, e.g. with spiral structure for generating turbulence
F25B 49/02 - Arrangement or mounting of control or safety devices for compression type machines, plants or systems
A circulating loop for transporting refrigeration to a remote location is connected serially between a Gifford-McMahon (GM) or GM type Pulse Tube cold head and the compressor. Either high pressure gas from the compressor can flow through the remote heat station before returning to the cold head or low pressure gas can flow from the cold head to the remote heat station before returning to the compressor. A first fraction of gas, which may include all of the gas at ambient temperature, enters a counter-flow heat exchanger, is cooled by the cold head, flows to the remote load, and then returns to ambient temperature as it flows through the counter-flow heat exchanger. The high or low pressure line may have a circulation control valve that diverts a second fraction of gas to flow directly between the cold head and compressor. A controller adjusts the circulation control valve to optimize the cooling of the load.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 49/00 - Arrangement or mounting of control or safety devices
F25B 41/20 - Disposition of valves, e.g. of on-off valves or flow control valves
This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. This invention provides redundancy between water cooling and air cooling if there is a blockage in the water or air supply by having air and water cooled after-coolers in series or parallel.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 43/02 - Arrangements for separating or purifying gases or liquidsArrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
The disclosed invention provides an unmodified scroll compressor with enhanced oil management system that enables the compressor system to compress helium. The compressor system includes a standard scroll compressor, oil separator, and an adsorber. The compressor includes a housing containing an orbiting scroll and a stationary scroll, a motor, and an oil sump in a bottom of the housing. The stationary scroll has one or more injection ports, and the housing contains a single discharge port, a return port, and a single injection port connected to the injection ports of the stationary scroll. The oil separator receives a mixture of helium and oil from the discharge port. The compressor system further includes a line bringing a first fraction of oil from the oil separator to the injection port, one or more lines bringing a second fraction of oil to the return port along with helium. The adsorber retains a third fraction of oil.
F04C 23/00 - Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluidsPumping installations specially adapted for elastic fluidsMulti-stage pumps specially adapted for elastic fluids
F04C 18/02 - Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
The disclosed invention provides a bridge voltage inversion circuit for vacuum gauge and a pressure gauge sensor that includes the bridge voltage inversion circuit. The bridge voltage inversion circuit for a pressure gauge includes a reference capacitance, a sensor capacitance, and a transformer including a primary winding and a secondary winding that outputs a bridge voltage. The reference capacitor is connected to a first side of the secondary winding of the transformer, and the sensor capacitor is connected to a second side of the secondary winding of the transformer. The sensor capacitor senses and responds to a pressure, and a capacitance of the sensor capacitor is at a minimum when the pressure is at vacuum. The capacitance of the sensor capacitor at vacuum is less than a capacitance of the reference capacitor.
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
G01L 21/12 - Vacuum gauges by measuring variations in the heat conductivity of the medium, the pressure of which is to be measured measuring changes in electric resistance of measuring members, e.g. of filamentsVacuum gauges of the Pirani type
13.
Thermal barrier between high-temperature sensor and electronics in a capacitance diaphragm gauge
A capacitive diaphragm gauge (CDG) is positioned in a pressure sensing section of a pressure measuring unit. The CDG is heated to maintain the CDG at a temperature selected to reduce contamination build-up on the diaphragm of the CDG. The pressure sensing section is connected to a first mounting interface of a thermal barrier. A second mounting interface of the thermal barrier is connected to an electronics section. The thermal barrier includes a plurality of struts that mechanically interconnect the two mounting interfaces. The struts have sizes selected to be sufficiently large to cantilever the electronics section from the sensing section. The sizes of the struts are selected to be sufficiently small to reduce the heat transfer from the first mounting interface to the second mounting interface to maintain the second mounting interface below a selected maximum temperature. The struts reduce heat transfer without reducing structural integrity.
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 19/00 - Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
G01L 19/06 - Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
14.
CO-AXIAL DOUBLE-INLET VALVE FOR PULSE TUBE CRYOCOOLER
A Gifford-McMahon (GM) type double-inlet pulse tube system providing cooling at cryogenic temperatures is provided. The system has a co-axial double-inlet valve that includes a base having an adjustable port, a fixed needle partially engaged in one end of the adjustable port, an adjustable needle partially engaged in another end of said adjustable port, and a body for housing the base, the fixed needle and the adjustable needle. The base is configured to be adjustable along an axial direction. The adjustable needle is arranged co-axially with the fixed needle. The adjustable port and the adjustable needle are configured to control an alternating current (AC) flow and a direct current (DC) flow between the stem port and the end port and to produce the DC flow in either direction between the stem port and the end port.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
A pneumatically driven cryogenic refrigerator operating primarily on the Gifford-McMahon (GM) cycle is switched from cooling to heating by a switch valve between a rotary valve and a drive piston that causes the displacer to reciprocate. The rotary valve has ports at two radii, one that cycles flow to the displacer and a second that cycles flow to the drive piston. Two ports cycle flow to the top of the drive piston, the “cooling” port optimizes the cooling cycle and the “heating” port provides a good heating cycle. A switch valve that changes the flow from one port to the other can be linearly or rotary actuated. The rotary valve does not reverse direction.
F25B 41/20 - Disposition of valves, e.g. of on-off valves or flow control valves
F25B 9/10 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point with several cooling stages
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
16.
Co-axtal, double-inlet valve for pulse tube cryocooler
A Gifford-McMahon (GM) type double-inlet pulse tube system providing cooling at cryogenic temperatures is provided. The system has a co-axial double-inlet valve that includes a base having an adjustable port, a fixed needle partially engaged in one end of the adjustable port, an adjustable needle partially engaged in another end of said adjustable port, and a body for housing the base, the fixed needle and the adjustable needle. The base is configured to be adjustable along an axial direction. The adjustable needle is arranged co-axially with the fixed needle. The adjustable port and the adjustable needle are configured to control an alternating current (AC) flow and a direct current (DC) flow between the stem port and the end port and to produce the DC flow in either direction between the stem port and the end port.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/10 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point with several cooling stages
A pneumatically driven cryogenic refrigerator operating primarily on the Gifford-McMahon (GM) cycle is switched from cooling to heating by a switch valve between a rotary valve and a drive piston that causes the displacer to reciprocate. The rotary valve has ports at two radii, one that cycles flow to the displacer and a second that cycles flow to the drive piston. Two ports cycle flow to the top of the drive piston, the "cooling" port optimizes the cooling cycle and the "heating" port provides a good heating cycle. A switch valve that changes the flow from one port to the other can be linearly or rotary actuated. The rotary valve does not reverse direction.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
18.
HYBRID DOUBLE-INLET VALVE FOR PULSE TUBE CRYOCOOLER
A double-inlet valve for a Gifford-McMahon (GM) type double-inlet pulse tube cryocooler system for providing cooling at cryogenic temperatures includes a fixed restrictor and a needle valve coupled to the fixed restrictor in parallel. The needle valve produces asymmetric flow. The combination of the fixed restrictor and the needle valve having an asymmetric flow provides improved alternating current (AC) flow characteristics and adjustability of direct current (DC) flow to increase the available cooling.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
19.
HYBRID DOUBLE-INLET VALVE FOR PULSE TUBE CRYOCOOLER
A double-inlet valve for a Gifford-McMahon (GM) type double-inlet pulse tube cryocooler system for providing cooling at cryogenic temperatures includes a fixed restrictor and a needle valve coupled to the fixed restrictor in parallel. The needle valve produces asymmetric flow. The combination of the fixed restrictor and the needle valve having an asymmetric flow provides improved alternating current (AC) flow characteristics and adjustability of direct current (DC) flow to increase the available cooling.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 41/20 - Disposition of valves, e.g. of on-off valves or flow control valves
This invention relates to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) or Brayton cycle. The objective of this invention is to provide redundancy by having a water cooled compressor manifolded to an air cooled compressor and sensors to detect faults so that an expander can be kept running if there is a failure in either the water or air supply.
A superconducting magnet device (10) comprises: a superconducting coil (12); a radiation shield (14) which thermally protects the superconducting coil (12); a main cold head (102) which cools the superconducting coil (12); a sub cold head (104) which cools the radiation shield (14); a shared compressor (106) which supplies coolant gas to the main cold head (102) and the sub cold head (104); a first temperature sensor (40) which measures the temperature of the radiation shield (14); a second temperature sensor (42) which measures the temperature of the superconducting coil (12); and a controller (110) which is configured to start up the sub cold head (104) for initial cooling of the superconducting magnet device (10), stop the sub cold head (104) on the basis of output from the first temperature sensor (40) or the second temperature sensor (42), and cause the main cold head (102) to operate in a state where the sub cold head (104) is stopped.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
Losses in the connecting line between the Pressure Wave Generator and the cold head of a GM type pulse tube refrigerator, are reduced while maintaining or improving upon the desirable features of a standard corrugated hose connecting line including vibration isolation, separation distance, and mounting convenience. The basic means are to reduce the internal void volume of the convolutions in a corrugated hose in combination with reducing the number of corrugations, adding fillers to the void volumes, and vibration absorbing coatings.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F16L 11/15 - Hoses, i.e. flexible pipes made of rigid material, e.g. metal or hard plastics corrugated
F16L 58/10 - Coatings characterised by the materials used by rubber or plastics
Losses in the connecting line between the Pressure Wave Generator and the cold head of a GM type pulse tube refrigerator, are reduced while maintaining or improving upon the desirable features of a standard corrugated hose connecting line including vibration isolation, separation distance, and mounting convenience. The basic means are to reduce the internal void volume of the convolutions in a corrugated hose in combination with reducing the number of corrugations, adding fillers to the void volumes, and vibration absorbing coatings.
The disclosed invention provides an unmodified scroll compressor with enhanced oil management system that enables the compressor system to compress helium. The compressor system includes a standard scroll compressor, oil separator, and an adsorber. The compressor includes a housing containing an orbiting scroll and a stationary scroll, a motor, and an oil sump in a bottom of the housing. The stationary scroll has one or more injection ports, and the housing contains a single discharge port, a return port, and a single injection port connected to the injection ports of the stationary scroll. The oil separator receives a mixture of helium and oil from the discharge port. The compressor system further includes a line bringing a first fraction of oil from the oil separator to the injection port, one or more lines bringing a second fraction of oil to the return port along with helium. The adsorber retains a third fraction of oil.
F04C 18/02 - Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
The disclosed invention provides a bridge voltage inversion circuit for vacuum gauge and a pressure gauge sensor that includes the bridge voltage inversion circuit. The bridge voltage inversion circuit for a pressure gauge includes a reference capacitance, a sensor capacitance, and a transformer including a primary winding and a secondary winding that outputs a bridge voltage. The reference capacitor is connected to a first side of the secondary winding of the transformer, and the sensor capacitor is connected to a second side of the secondary winding of the transformer. The sensor capacitor senses and responds to a pressure, and a capacitance of the sensor capacitor is at a minimum when the pressure is at vacuum. The capacitance of the sensor capacitor at vacuum is less than a capacitance of the reference capacitor.
G01L 1/14 - Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
A heat station for a GM or Stirling cycle expander provides a versatile, efficient, and cost effective means of transferring heat from a remote load at cryogenic temperatures that is cooled by a circulating cryogen to the gas in a GM or Stirling cycle expander as the gas flows between a regenerator and a displaced volume. The heat exchanger includes a shell that has external and internal fins that are thermally connected, are aligned parallel to the axis of the shell, and are enclosed in a housing having a single port on the bottom of the housing.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F28F 3/02 - Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
F28D 21/00 - Heat-exchange apparatus not covered by any of the groups
A capacitive diaphragm gauge (CDG) is positioned in a pressure sensing section of a pressure measuring unit. The CDG is heated to maintain the CDG at a temperature selected to reduce contamination build-up on the diaphragm of the CDG. The pressure sensing section is connected to a first mounting interface of a thermal barrier. A second mounting interface of the thermal barrier is connected to an electronics section. The thermal barrier includes a plurality of struts that mechanically interconnect the first mounting interface to the second mounting interface. The struts have sizes selected to be sufficiently large to cantilever the electronics section from the sensing section. The sizes of the struts are selected to be sufficiently small to reduce the heat transfer from the first mounting interface to the second mounting interface to maintain the second mounting interface below a selected maximum temperature.
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
A cryogenic refrigerator system with heaters is constructed in modular form to serve as a portable servicing system to warm up and then cool down a target object by circulating a gaseous cryogen through a target object cryostat without moving the target object or breaking its vacuum. The main module is a refrigerator cryostat containing a fan that circulates gas through one or more heat exchangers which can warm or cool the gas by heaters and by one or more GM or Brayton cycle expanders. Additional components including one or more compressors, a gas charge and vent assembly, a control system, gas lines, power lines, and vacuum jacketed transfer lines can be assembled in the main module or additional modules. An example is a system that can be wheeled through a hospital to service a MRI cryostat.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F17C 3/08 - Vessels not under pressure with provision for thermal insulation by vacuum spaces, e.g. Dewar flask
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
A heat station for a GM or Stirling cycle expander provides heat transfer from a remote load at cryogenic temperatures that is cooled by a circulating cryogen to the gas in a GM or Stirling cycle expander as the cryogen between a regenerator and a displaced volume. The heat exchanger includes a shell that has external and internal fins thermally connected to the shell that are aligned parallel to the axis of the shell and enclosed in a housing having an inlet port and an outlet port on the bottom of the housing.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F28F 3/02 - Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
A heat station for a GM or Stirling cycle expander provides a versatile, efficient, and cost effective means of transferring heat from a remote load at cryogenic temperatures that is cooled by a circulating cryogen to the gas in a GM or Stirling cycle expander as it flows between a regenerator and a displaced volume. The heat exchanger comprises a shell that has external and internal fins thermally connected to it that are aligned parallel to the axis of the shell and enclosed in a housing having an inlet port and an outlet port on the bottom of the housing.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
33.
UNIVERSAL CONTROLLER FOR INTEGRATION OF CRYOGENIC EQUIPMENT, REQUIRING DIFFERENT CONTROL MECHANISMS, ONTO A SINGLE OPERATING PLATFORM
A universal controller for integration of cryogenic equipment, requiring different control mechanisms, onto a single operating platform. The universal controller may include a power supply element that is configured to simultaneously drive a plurality of cryogenic devices that have different power supply requirements and a protocol translator element that is configured to enable communication between a plurality' of cryogenic devices that use different, incompatible communication protocols, wherein the protocol translator element translates communications sent by a first type of cryogenic device from a first cryogenic device communication protocol into a second cryogenic device communication protocol and translates communications sent by a second type of cryogenic device from a second cryogenic device communication protocol into the first cryogenic device communication protocol, enabling the first type of cryogenic device and the second type of cryogenic device to communicate with each other.
F25B 49/02 - Arrangement or mounting of control or safety devices for compression type machines, plants or systems
H04Q 9/00 - Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
34.
SYSTEM FOR WARMING-UP AND COOLING-DOWN A SUPERCONDUCTING MAGNET
A cryogenic refrigerator system with heaters is constructed in modular form to serve as a portable servicing system to warm up and then cool down a target object by circulating a gaseous cryogen through a target object cryostat without moving the target object or breaking its vacuum. The main module is a refrigerator cryostat containing a fan that circulates gas through one or more heat exchangers which can warm or cool the gas by heaters and by one or more GM or Brayton cycle expanders. Additional components including one or more compressors, a gas charge and vent assembly, a control system, gas lines, power lines, and vacuum jacketed transfer lines can be assembled in the main module or additional modules. An example is a system that can be wheeled through a hospital to service a MRI cryostat.
A cryogenic refrigerator system with heaters is constructed in modular form to serve as a portable servicing system to warm up and then cool down a target object by circulating a gaseous cryogen through a target object cryostat without moving the target object or breaking its vacuum. The main module is a refrigerator cryostat containing a fan that circulates gas through one or more heat exchangers which can warm or cool the gas by heaters and by one or more GM or Brayton cycle expanders. Additional components including one or more compressors, a gas charge and vent assembly, a control system, gas lines, power lines, and vacuum jacketed transfer lines can be assembled in the main module or additional modules. An example is a system that can be wheeled through a hospital to service a MRI cryostat.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 49/02 - Arrangement or mounting of control or safety devices for compression type machines, plants or systems
An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. A valve connecting the warm end of the cylinder to a buffer tank allows a partial expansion and recompression of gas in the cold displaced volume that increases the refrigeration produced in each cycle with the same compressor flow rate.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 41/20 - Disposition of valves, e.g. of on-off valves or flow control valves
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
37.
Cryogenic expander with collar bumper for reduced noise and vibration characteristics
A cryogenic expander maximizes the energy absorbing capacity of bumpers that prevent the displacer or piston in a pneumatically driven expander from hitting the cold or warm end of a cylinder. A collar at the warm end of the piston which has the same outside diameter as the piston and a lip at the warm end that engages an “O” ring before the piston hits the cold end or bottom of the cylinder. The warm end of the collar also engages an “O” ring before the pistons hits the warm end or top of the cylinder. Having “O” rings that are near the maximum diameter of the cylinder maximizes the amount of energy they can absorb, and thus permits quiet operation of larger size expanders than prior designs.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F02G 1/04 - Hot gas positive-displacement engine plants of closed-cycle type
This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. This invention provides redundancy between water cooling and air cooling if there is a blockage in the water or air supply by having air and water cooled after-coolers in series or parallel.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 43/02 - Arrangements for separating or purifying gases or liquidsArrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
This invention relates to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) or Brayton cycle. The objective of this invention is to provide redundancy by having a water cooled compressor manifolded to an air cooled compressor and sensors to detect faults so that an expander can be kept running if there is a failure in either the water or air supply.
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25B 1/00 - Compression machines, plants or systems with non-reversible cycle
An oil lubricated helium compressor system is located in an indoor environment where the ambient air temperature is between 15°C and 30°C. The system includes a compressor, a separator internal or external to the compressor that receives a mixture of compressed helium and oil and discharges helium and oil through separate ports, a water cooled after-cooler for effecting cooling of the helium and oil, an air cooled after-cooler for effecting cooling of the helium and oil, the air cooled after-cooler including a heat exchanger and a fan, the both coolers are connected in series, a first line extending from the helium discharge port and passing through the water cooled after-cooler and the air cooled after-cooler the helium being cooled by one or both the water cooled after-cooler and the air cooled after-cooler; and a second line extending from the oil discharge port through both coolers.
This invention relates to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) or Brayton cycle. The objective of this invention is to provide redundancy by having a water cooled compressor manifolded to an air cooled compressor and sensors to detect faults so that an expander can be kept running if there is a failure in either the water or air supply.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. A valve connecting the warm end of the cylinder to a buffer tank allows a partial expansion and recompression of gas in the cold displaced volume that increases the refrigeration produced in each cycle with the same compressor flow rate.
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
A hybrid expander for producing refrigeration at a cryogenic temperature includes a Brayton expander producing refrigeration at a first temperature; a GM expander producing refrigeration at a second temperature, the first temperature being colder than the second temperature, the second temperature being 200K or less. A high pressure line receives a gas from a compressor at a first pressure and supplies it at the first pressure to the Brayton expander and the GM expander simultaneously. A low pressure line returns the gas to the compressor at a second pressure from the Brayton expander and the GM expander, the first pressure being greater than the second pressure. The Brayton expander piston is attached to the cold end of the GM expander displacer and the Brayton expander piston and the GM expander displacer reciprocating together.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/10 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point with several cooling stages
A means and a method to cool down an MRI magnet, in a cryostat that is designed for a maximum pressure of about 0.2 MPa, are described which use cold helium output from a Brayton cycle refrigerator at a pressure of about 0.8 MPa to exchange heat with helium in the MRI cryostat in a coupling heat exchanger that is located removeably in or proximate the neck tube of the MRI cryostat. A circulator drives helium from the MRI cryostat through the coupling heat exchanger.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25B 45/00 - Arrangements for charging or discharging refrigerant
F25B 19/00 - Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
G01R 33/38 - Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
F25D 19/00 - Arrangement or mounting of refrigeration units with respect to devices
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
G01R 33/3815 - Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field using electromagnets with superconducting coils, e.g. power supply therefor
45.
Method and system for monitoring gas pressure for reference cavity of capacitance diaphragm gauge
A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 21/34 - Vacuum gauges by making use of ionisation effects using electric discharge tubes with cold cathodes
G01L 9/14 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means involving the displacement of magnets, e.g. electromagnets
A system and method mitigate the effects of these external vibrations on a capacitance diaphragm gauge by sensing the motion of the diaphragm at the first natural frequency of the diaphragm of the CDG. The presence of the natural frequency signals superimposed on the pressure signal is determined by sensing variations in the output of a sensor at or near the known natural frequency of the diaphragm and filtering that known low frequency from the output. The filtered signal is used in a feedback circuit to impose electrostatic forces on the diaphragm. The imposed electrostatic forces oppose the motion created by the external vibration to suppress the effects of the vibration on the pressure measured by the CDG.
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 27/00 - Testing or calibrating of apparatus for measuring fluid pressure
47.
Apparatus and method for automatic detection of diaphragm coating or surface contamination for capacitance diaphragm gauges
A system and a method detect contamination of a diaphragm in a capacitance diaphragm gauge wherein a contaminated diaphragm deflects less in the presence of pressure than an uncontaminated diaphragm. The system and method measure a base pressure. A DC voltage is applied between the diaphragm and a fixed electrode to cause the diaphragm to deflect to simulate an effective pressure. The system and method measure a combined pressure caused by the base pressure and the effective pressure. The system and method subtract the base pressure to determine the effective pressure caused by the static diaphragm deflection. If the measured effective pressure is less than an acceptable effective pressure, the system and method determine that the diaphragm is contaminated.
G01L 27/00 - Testing or calibrating of apparatus for measuring fluid pressure
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
A hybrid expander combines a Brayton engine first stage with one or more GM colder stages that uses the flow from the Brayton engine to provide refrigeration at one or more remote heat stations.
F25B 7/00 - Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
F25B 41/06 - Flow restrictors, e.g. capillary tubes; Disposition thereof
F25B 49/00 - Arrangement or mounting of control or safety devices
A hybrid expander combines a Brayton engine first stage with one or more GM colder stages that uses the flow from the Brayton engine to provide refrigeration at one or more remote heat stations.
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/10 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point with several cooling stages
50.
Brayton cycle engine with high displacement rate and low vibration
To provide refrigeration below 200 K, a Brayton cycle engine contains a light reciprocating piston. The refrigerator includes a compressor, a gas-balanced reciprocating engine having a cold rotary valve, a counterflow heat exchanger, a gas storage volume with valves that can adjust system pressures, a variable speed engine and a control system that controls gas pressure, engine speed, and the speed of the piston. The engine is connected to a load such as a cryopanel, for pumping water vapor, through insulated transfer lines.
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F04B 15/08 - Pumps adapted to handle specific fluids, e.g. by selection of specific materials for pumps or pump parts for liquids near their boiling point, e.g. under subnormal pressure the liquids having low boiling points
F02G 3/02 - Combustion-product positive-displacement engine plants with reciprocating-piston engines
F02G 1/02 - Hot gas positive-displacement engine plants of open-cycle type
51.
Multi-axis tilt sensor for correcting gravitational effects on the measurement of pressure by a capacitance diaphragm gauge
A system and method compensate for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG). The CDG generates a measured absolute pressure value in response to an applied absolute pressure on an input of the CDG. The CDG is subjected to a variable orientation of the CDG with respect to the earth's surface that can cause inaccurate pressure measurements. A pressure measuring circuit generates a measured value of an applied absolute pressure provided to an input of the CDG. A tilt sensor generates at least one tilt sensor output value that is responsive to an orientation of the CDG with respect to the earth's surface. A processing system adjusts the measured absolute pressure value by a calibration factor to generate a calibrated absolute pressure value representing the applied absolute pressure, wherein the calibration factor is selected in response to the at least one tilt sensor output value.
G01L 27/00 - Testing or calibrating of apparatus for measuring fluid pressure
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
G01L 19/02 - Arrangements for preventing, or for compensating for, effects of inclination or acceleration of the measuring deviceZero-setting means
52.
Method and apparatus for acquiring noise reduced high frequency signals
A system and method receive the output signal from a capacitance diaphragm gauge (CDG) and generate a noise reduced output signal. An input signal processing circuit receives an input signal from a signal source that drives the CDG. The input signal processing circuit generates a segment of N normalized digital samples of the input signal. An output signal processing circuit receives the output signal from the CDG and generates M segments of N digital samples of the CDG output signal and averages the corresponding samples in the M segments to generate a signal segment of N averaged samples. Each of the N averaged samples is multiplied by a corresponding one of the N normalized samples to generate N products. The N products are averaged to generate an average product, which is multiplied by a constant to generate a system output signal with reduced noise.
H03B 1/00 - GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNERGENERATION OF NOISE BY SUCH CIRCUITS Details
H03K 5/1252 - Suppression or limitation of noise or interference
An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. Low pressure on a piston drive stem provides a force imbalance to move the piston towards the warm end.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
54.
Method and apparatus for damping diaphragm vibration in capacitance diaphragm gauges
A system and method mitigate the effects of these external vibrations on a capacitance diaphragm gauge by sensing the motion of the diaphragm at the first natural frequency of the diaphragm of the CDG. The presence of the natural frequency signals superimposed on the pressure signal is determined by sensing variations in the output of a sensor at or near the known natural frequency of the diaphragm and filtering that known low frequency from the output. The filtered signal is used in a feedback circuit to impose electrostatic forces on the diaphragm. The imposed electrostatic forces oppose the motion created by the external vibration to suppress the effects of the vibration on the pressure measured by the CDG.
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
55.
Automatic calibration adjustment of capacitance diaphragm gauges to compensate for errors due to changes in atmospheric pressure
In order to mitigate the negative effects of a change in atmospheric pressure, an improved capacitance diaphragm gauge (CDG) sensor incorporates an independent ambient atmospheric pressure sensor near the CDG sensor body. The ambient atmospheric sensor is located outside the CDG sensor body to sense the ambient atmospheric pressure surrounding the CDG sensor body. The ambient atmospheric sensor provides an output that represents the ambient atmospheric pressure. A sensor output processing circuit receives the output of the ambient atmospheric sensor as well as the output of the CDG sensor. The processing circuit utilizes the output from the ambient atmospheric pressure sensor to fine tune the CDG measurement of pressure by executing an in situ, real time, automatic calibration adjustment of the CDG.
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
G01L 27/00 - Testing or calibrating of apparatus for measuring fluid pressure
G01L 7/08 - Measuring the steady or quasi-steady pressure of a fluid or a fluent solid material by mechanical or fluid pressure-sensitive elements in the form of elastically-deformable gauges of the flexible-diaphragm type
56.
Multi-axis tilt sensor for correcting gravitational effects on the measurement of pressure by a capacitance diaphragm gauge
A system and method compensate for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG). The CDG generates a measured absolute pressure value in response to an applied absolute pressure on an input of the CDG. The CDG is subjected to a variable orientation of the CDG with respect to the earth's surface that can cause inaccurate pressure measurements. A pressure measuring circuit generates a measured value of an applied absolute pressure provided to an input of the CDG. A tilt sensor generates at least one tilt sensor output value that is responsive to an orientation of the CDG with respect to the earth's surface. A processing system adjusts the measured absolute pressure value by a calibration factor to generate a calibrated absolute pressure value representing the applied absolute pressure, wherein the calibration factor is selected in response to the at least one tilt sensor output value.
G01L 27/00 - Testing or calibrating of apparatus for measuring fluid pressure
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
57.
Apparatus and method for automatic detection of diaphragm coating or surface contamination for capacitance diaphragm gauges
A system and a method detect contamination of a diaphragm in a capacitance diaphragm gauge wherein a contaminated diaphragm deflects less in the presence of pressure than an uncontaminated diaphragm. The system and method measure a base pressure. A DC voltage is applied between the diaphragm and a fixed electrode to cause the diaphragm to deflect to simulate an effective pressure. The system and method measure a combined pressure caused by the base pressure and the effective pressure. The system and method subtract the base pressure to determine the effective pressure caused by the static diaphragm deflection. If the measured effective pressure is less than an acceptable effective pressure, the system and method determine that the diaphragm is contaminated.
A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.
G01L 9/12 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance
G01L 21/34 - Vacuum gauges by making use of ionisation effects using electric discharge tubes with cold cathodes
G01L 9/00 - Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by electric or magnetic pressure-sensitive elementsTransmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
A means and a method to cool down an MRI magnet, in a cryostat that is designed for a maximum pressure of about 0.2 MPa, are described which use cold helium output from a Brayton cycle refrigerator at a pressure of about 0.8 MPa to exchange heat with helium in the MRI cryostat in a coupling heat exchanger that is located removeably in or proximate the neck tube of the MRI cryostat. A circulator drives helium from the MRI cryostat through the coupling heat exchanger.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25B 19/02 - Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour using fluid jet, e.g. of steam
A61B 5/055 - Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fieldsMeasuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
60.
Method and apparatus for acquiring noise reduced high frequency signals
A system and method receive the output signal from a capacitance diaphragm gauge (CDG) and generate a noise reduced output signal. An input signal processing circuit receives an input signal from a signal source that drives the CDG. The input signal processing circuit generates a segment of N normalized digital samples of the input signal. An output signal processing circuit receives the output signal from the CDG and generates M segments of N digital samples of the CDG output signal and averages the corresponding samples in the M segments to generate a signal segment of N averaged samples. Each of the N averaged samples is multiplied by a corresponding one of the N normalized samples to generate N products. The N products are averaged to generate an average product, which is multiplied by a constant to generate a system output signal with reduced noise.
H03B 1/00 - GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNERGENERATION OF NOISE BY SUCH CIRCUITS Details
To provide refrigeration below 200 K, a Brayton cycle engine contains a light reciprocating piston. The refrigerator includes a compressor, a gas-balanced reciprocating engine having a cold rotary valve, a counterflow heat exchanger, a gas storage volume with valves that can adjust system pressures, a variable speed engine and a control system that controls gas pressure, engine speed, and the speed of the piston. The engine is connected to a load such as a cryopanel, for pumping water vapor, through insulated transfer lines.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F01B 23/00 - Adaptations of machines or engines for special useCombinations of engines with devices driven thereby
F04B 35/00 - Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
Faster cool down time is achieved in a low profile cryopump by having heat transferred directly from the inlet louver to the first stage heat station through one or more tapered thermal busses, and by obviating the need of a thermal shield over the second stage cylinder of the expander by having second stage cryopanels that form a nested tent like structure, at least one of which, extends over the cylinder.
A means of rapidly melting a large quantity of type II cryogen in a cryopump that is configured to contain the liquid in the warm cryopanel with the inlet to the cryopump facing up or sideways, and venting the liquid and gas in a controlled way. Rapid melting is preferably accomplished by flowing a purge gas that will condense on the cryodeposit. By not allowing the liquid to drain onto the vacuum housing the evaporation rate is limited and the maximum pressure in the cryopump can be controlled by the purge gas flow rate.
The primary invention is to cool a water vapor cryopump using a Gas Balanced Brayton cycle refrigerator. The refrigerator is comprised of a compressor, a gas balanced reciprocating engine and a counterflow heat exchanger. It is connected to the cryopump through insulated transfer lines. Options include a gas storage volume with valves that can adjust system pressures, a variable speed engine, gas lines between the compressor and cryopanel that by-pass the engine, and a gas line that by-passes the heat exchanger. This system can cool down and warm up rapidly, rapidly warm and cool the cryopanel without warming the engine, and reduce power input when the cryopanel heat load is reduced.
F04B 37/08 - Pumps specially adapted for elastic fluids and having pertinent characteristics not provided for in, or of interest apart from, groups for evacuating by thermal means by condensing or freezing, e.g. cryogenic pumps
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
65.
GAS BALANCED BRAYTON CYCLE COLD WATER VAPOR CRYOPUMP
The primary invention is to cool a water vapor cryopump using a Gas Balanced Brayton cycle refrigerator. The refrigerator is comprised of a compressor, a gas balanced reciprocating engine and a counterflow heat exchanger. It is connected to the cryopump through insulated transfer lines. Options include a gas storage volume with valves that can adjust system pressures, a variable speed engine, gas lines between the compressor and cryopanel that by -pass the engine, and a gas line that by-passes the heat exchanger. This system can cool down and warm up rapidly, rapidly warm and cool the cryopanel without warming the engine, and reduce power input when the cryopanel heat load is reduced.
F04B 37/08 - Pumps specially adapted for elastic fluids and having pertinent characteristics not provided for in, or of interest apart from, groups for evacuating by thermal means by condensing or freezing, e.g. cryogenic pumps
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. Low pressure on a piston drive stem provides a force imbalance to move the piston towards the warm end.
F01B 9/04 - Reciprocating-piston machines or engines characterised by connections between pistons and main shafts, not specific to groups with rotary main shaft other than crankshaft
F01B 23/00 - Adaptations of machines or engines for special useCombinations of engines with devices driven thereby
F01B 25/10 - Arrangements or adaptations of working-fluid admission or discharge valves
F01B 21/04 - Combinations of two or more machines or engines the machines or engines being not all of reciprocating-piston type, e.g. of reciprocating steam engine with steam turbine
An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. Low pressure on a piston drive stem provides a force imbalance to move the piston towards the warm end.
A refrigeration system for minimizing the cool down time of a mass to cryogenic temperatures including a compressor, an expander, a gas storage tank, interconnecting gas lines, and a control system. The compressor output is maintained near its maximum capability by maintaining near constant high and low pressures during cool down, gas being added or removed from the storage tank to maintain a near constant high pressure, and the speed of said expander being adjusted to maintain a near constant low pressure, no gas by-passing between high and low pressures.
An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. The piston and valves can be either mechanically or pneumatically actuated and the pressures above and below the piston can be nearly equal by virtue of a regenerator that connects the two spaces or by valves.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F25D 9/00 - Devices not associated with refrigerating machinery and not covered by groups Combinations of devices covered by two or more of the groups
F25B 9/14 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
F25B 9/06 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using expanders
This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. The objective of this invention is to keep the oil separator and absorber, which are components in an oil lubricated, helium compressor, in an indoor air conditioned environment while rejecting at least 65% of the heat from the compressor outdoors during the summer. The balance of the heat is rejected to either the indoor air conditioned air, or cooling water. This is accomplished by circulating hot oil at high pressure to an outdoor air cooled heat exchanger and returning cooled oil to the compressor inlet, while hot high pressure helium is cooled in an air or water cooled heat exchanger in an indoor assembly that includes the compressor, an oil separator, an oil absorber, and other piping and control components. It is an option to reject the heat from the oil to the indoor space during the winter to save on the cost of heating the indoor space.
A rotary valve unit which reduces the torque required to turn the valve disc, and the amount of wear dust that is blown into the cold head, using differential gas forces to keep the valve disc in contact with the valve seat, and which enables larger diameter valve discs to be utilized for multi-ported pulse tubes that have less force on the face of the valve disc, resulting in reduced torque and reduced wear rate.
F25B 9/00 - Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
F16K 11/074 - Multiple-way valves, e.g. mixing valvesPipe fittings incorporating such valvesArrangement of valves and flow lines specially adapted for mixing fluid with all movable sealing faces moving as one unit comprising only sliding valves with pivoted closure members with flat sealing faces
F16K 31/02 - Operating meansReleasing devices electricOperating meansReleasing devices magnetic
